1. Field of the Invention
The present inventton relates to a socket for an electrical part for detachably holding and accommodating an electrical part such as a semiconductor device (called as xe2x80x9cIC packagexe2x80x9d hereinlater).
2. Related Art of the Invention
In a known art, there has been provided an IC socket, as xe2x80x9csocket for an electrical partxe2x80x9d for detachably holding and accommodating an xe2x80x9cIC packagexe2x80x9d as an electrical part.
Such IC socket has a socket body provided with a contact pin which contacts a terminal of the IC package so as to establish an electrical connection and also has an open/close member to be rotatable so that when the open/close member is closed, the IC package accommodated on the socket body is pressed.
This open/close member is urged, by means of twist coil spring, towards a closing direction (i.e., a direction for urging the IC package), and on the contrary, is opened, against the urging force of the twist coil spring, by lowering an operation member which is disposed to the socket body to be vertically movable. According to this manner, the IC package can be accommodated in or taken out from the socket body.
When the IC package is pressed by the open/close member, the terminal of the IC package and the contact pin of the IC socket are contacted at a predetermined pressure.
The open/close member is also provided with a heat sink, and in its contacting state to the IC package, heat of the IC package is radiated.
However, in such conventional structure of the IC socket, the open/close member is urged by the twist coil spring towards the closing direction, the terminal of the IC package is contacted to the contact pin by this urging force, and the open/close member is opened by rotating it against the urging force of the twist coil spring. Accordingly, there is a limit to increasing of the urging force of the twist coil spring in order to ensure a desired contacting pressure, and the increasing of the urging force thereof results in a large force to open the open/close member, thus providing conflicting function or problem and hence being inconvenient.
An object of the present invention is therefore to substantially eliminate problems or inconveniences encountered in the prior art mentioned above and to provide a socket for an electrical part comprising:
a socket body having an electrical part accommodation portion;
a contact pin provided for the socket body so as to be contacted to or separated from a terminal of the electrical part;
an open/close member provided for the socket body for pressing the electrical part accommodated on the accommodation portion of the socket body; and
an operation member disposed for the socket body to be vertically movable so as to open or close the open/close member,
the open/close member including a pressing member for pressing the electrical part and a link mechanism for supporting the pressing member to be openable, the link mechanism comprising a first link disposed to be rotatable to the pressing member and the socket body and a second link disposed to be rotatable to the first link and the operation member,
wherein when the operation member is moved downward, one end side of the second link is lowered so as to rotate the first link about the socket body side through the second link and to thereby displace the pressing member from a pressing position at which the electrical part is pressed to a retired position at which the electrical part is attached to or detached from the electrical part accommodation portion, and on the other hand, when the operation member is moved upward, one end side of the second link is moved upward so as to rotate the first link about the socket body side and to displace the pressing member to the pressing position from the retired position.
According to the present invention of the aspect mentioned above, when the operation member is moved downward, one end side of the second link is lowered so as to rotate the first link about the socket body side through the second link and thereby to displace the pressing member from a pressing position at which the electrical part is pressed to a retired position at which the electrical part is attached to or detached from the electrical part accommodation portion, so that the depressing force to the operation member for opening the open/close member is made smaller in comparison with a conventional structure because of no need of a force against the urging force of the twist coil spring for ensuring the pressing force of the heat sink.
Furthermore, in the closed state of the open/close member, when a force for opening the open/close member due to the reaction force from the electrical part acts on the open/close member, the second link acts as strut member, without using any twist coil spring as in the conventional structure, to thereby prevent the opening motion of the open/close member, thus ensuring the contacting pressure of the contact portion of the contact pin to the terminal of the electrical part.
In a preferred embodiment of the above aspect, the first link includes a first link outside member and a first link inside member, which are arranged in parallel with a predetermined interval. The second link comprises a pair of side plates disposed to both sides of the pressing member and a coupling bridge portion coupling the side plates.
The pressing member may be a heat sink carrying out heat radiation through abutment against the electrical part.
The socket body may comprise a base portion to which a number of contact pins to be contacted to the terminals of the electrical part are arranged and a floating plate disposed above the base plate to be vertically movable with respect thereto, the floating plate having the electrical part accommodation portion.
The operation member has side portions to which ventilation passages are formed respectively so as to establish air circulation inside and outside thereof.
According to such preferred embodiment, the parallel arrangement of the first link outside and inside members makes it possible to suppress the deformation thereof even if any horizontal force is applied. In addition, in a case where a one-side pressing is applied to the operation member, the inclination of the pressing member can be largely reduced by unifying the first link members disposed both the lateral outside and inside thereof.
The nature and further characteristic features of the present invention will be made more clear from the following descriptions made with reference to the accompanying drawings.